We just bought a home and added a new master bath etc (3 1/2 bath now) and with 3 kids we run through a good bit of laundry & baths. Anyway, now that we're living here, the pressure is a bit low and can be almost like our camper if any other plumbing fixture is running.

Curently here's what we have:
- 120ft well drilled in 2001 with a 2" casing. According to records, water level is at 56ft
- 1.0hp Goulds 2 stage deep well jet pump model sj10.
- Goulds v60 (60 gal equiv I think) bladder tank feeding 1" line to house about 45ft away.
- 3 1/2 bath house, some irrigation of flower beds & garden regularly with 3 kids and a number of house guests.
- 30/50 Pressure switch is now set to about 42/64. Pump seems to struggle at about 70psig

Problem:
- decent pressure initially, but drops as soon as the tank is no longer helping.
- pump can only hold about 40psi with one hose bid open and nothing else.
- our last house had a 6" deep well (585ft) with a large submersible pump & 220gal galvanized tank. It could recover even with multiple sprinklers or showers and still build up enough pressure to shut off. This was a different location, and expensive, but served us ideally.

With what I have now, I hate to go too crazy as we have really good, clean reliable water and the well is pretty new. I'm thinking that perhaps adding a large (315gal equiv) bladder tank with our 60gal equiv tank would allow 2 or more showers or God forbid a load of cloths washing simultaneously with good pressure before relying only on the pump. What do you guys think? I don't think that a CSV will do much improvement as the pump can't really develop enough working pressure and flow for us.

I realize that a pump is (maybe a 1.5-2.0hp 3 stage) would be a better solution long term. However, right now I can't find out much about the well's production capability, and I hate to overload it. I figure that I could get a couple of years out of this pump until we start irrigating our flowerbeds (not yet built) and garden. Then I can upgrade the pump and the large tank(s) would be necessary anyway.

Any pros/cons to the large pressure tank with the current pump setup? All advise is appreciated.
Thanks.